An upsurge in fighting has resulted in increased casualties among Ukrainian soldiers, and restrictions on OSCE monitors. The US is calling on Russia to honor the Ukraine ceasefire under the Minsk agreements.

The United States on Sunday condemned an attack on special monitoring missions in eastern Ukraine and called on Russia and separatist forces to immediately observe the ceasefire under the Minsk agreements."We call on Russia and the separatist forces it backs to immediately observe the ceasefire, withdraw all heavy weapons, and allow full and unfettered access to the OSCE monitors," the State Department said.

State Department spokesman Mark Toner said the United States was closely monitoring growing violence in eastern Ukraine and the failure of the combined Russian and separatist forces to abide by a ceasefire, agreed to two years ago in Minsk."We condemn Friday's targeting of OSCE Special Monitoring Mission (SMM) monitors and the seizure of a SMM unmanned aerial vehicle by combined-Russian separatist forces," Toner said, referring to the civilian observers with the Organization for Security and Cooperation in Europe."It is imperative that these forces halt their attacks on civilian infrastructure, including the Donetsk water filtration station."